Multilayered Sliding Member for Crack Propagation Resistance
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Solution Overview
Problem
Articulated couplings with sliding elements are prone to cracking and flaking due to external stresses, leading to a loss of surface properties and increased friction, which necessitates frequent replacement.
Innovation Solution
A sliding element composed of a stack of 1000 to 10,000 nanometric layers of intermetallic materials like TiAlN or AlCrN, with each layer having an average thickness of 0.5 to 5 nm, is used to prevent crack propagation and enhance mechanical properties, such as hardness and friction coefficient.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single-piece inner ring is used to provide sliding action, then the structure is simple, but the ring is sensitive to external stresses causing cracks and flaking
Solution Approach 1:
The inner ring is divided into multiple thin layers (1 to 100 layers) with each layer being independent. This segmentation allows stress to be distributed across layers rather than concentrating in a single piece, preventing crack propagation and flaking while maintaining the sliding function.
Solution Approach 2:
The sliding element is constructed as a composite structure with multiple layers of different materials (first material and second material) with different coefficients of thermal expansion. This composite structure provides both mechanical strength and resistance to thermal and mechanical stresses, eliminating the cracking and flaking issues of single-material rings.
2Reliability
If multiple layers of intermetallic materials are deposited to prevent crack propagation, then reliability is improved, but manufacturing complexity increases
Solution Approach 1:
The patent specifies precise parameters for the multilayer structure: layer thickness (1 nm to 100 nm), number of layers (1 to 100), and material composition ratios. These controlled parameters enable the deposition process to be standardized and replicated, making the complex manufacturing process manageable and consistent.
Solution Approach 2:
The mechanical assembly of multiple separate rings is replaced by a deposited multilayer structure where layers are bonded at the atomic level. This substitution of mechanical construction with material deposition simplifies the manufacturing process by eliminating the need for precise mechanical fitting and assembly of multiple components.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The multilayer structure effectively limits the propagation of external stresses, maintaining the sliding element's properties and extending its service life, even in harsh environments, by preventing flaking and ensuring consistent friction coefficients.
Implementation Method 1
said sliding element including a stack of at least two layers of an intermetallic material, making it possible to prevent the propagation of a crack from one layer to the next layer
Implementation Method 2
The sliding element may include at least at least one TiAlN-based layer or an equivalent in terms of tribological properties. The sliding element may include at least one AlCrN-based layer or an equivalent in terms of tribological properties
Data Source
AI summary
A seal designed, in particular, to connect together two ducts for carrying fluid or gas, including: a female endpiece having a first end, a male endpiece having a second end, the male endpiece being received in the female endpiece. The seal includes a sliding element situated between the first end of the female endpiece and the second end of the male endpiece, the sliding element including a stack of at least two layers of an intermetallic material, making it possible to prevent the propagation of a crack from one layer to the next layer.